Digital Communication Protocols

7/25/2019 Digital Communication Protocols

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Digital Communication Protocol

Minghui Zhang, Senior R&D Hardware EngineerKalyanramu Vemishetty, Senior Embedded Systems En


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Agenda

RIO Overview

Design with Timing Software Architecture

Q&A


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RIO Hardware

Expansion I/O

MXI-Express RIO Ethernet RIO EtherCAT RIO Wireless

CompactRIO and NI Single-Board RIO

Value

PXI, PC RIO (R Series, NI

FlexRIO)

High PerformanceValue Performance


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RIO Hardware

I/O Frequency

I/O


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RIO Hardware


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SPI Example

CPOL = 0SCK Idle as

CPHA = 0

Send MOS

@ SCK Falling

Sample MIS

@ SCK Rising

0 0

Master SPI

- Select SPI configuration Based on ADC


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SPI Example

- Synchronous Design

SPIMaster

ControlInterface

Ba

ckplane

Interface

SPI Interface

SPI Clock Base Clock


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SPI Example

Synchronous deGenerate S

@ TopClk R

Sample MIS

@ TopClk R

Design with Tim

SCTLOutput Sign

Input Signa

- SPI Protocol Design


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SPI Example

Single Cycle Tim

- SPI Protocol Timing


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SPI Example

Output SignalsArbitrate

- SPI Protocol Output Signals


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SPI Example



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SPI Example

Output SignalsSync Regis



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SPI Example

Input SignalsSync Regis

Setup time Hold time

- SPI Protocol Input Signals


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Designing FPGA Digital Communication Protoco

Communication

Protocol Core

Communication

Protocol API

Communication

Protocol Abstraction


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Case Study

Acquire Data from ADC using SPI Communication Protocol

ADCSPI

FPGA


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Communication Protocol Core

Use State Machine

DIO 0Arbitratio

n Logic

True

False

C i i P l C


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Decouple I/O from State

C i i P l C


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Get I/O ValuesSet I/O V

SPI Core

(State Machine)

Initialize DIO Lines

D L k C d


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Deep Look at Code

Read SPI Digital Lines

D L k t C d


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Deep Look at Code

Write SPI Digital Lines

C i ti P t l C


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Desktop Execution Node Simulated SPI Core Waveform

D i i FPGA Di it l C i ti P t


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Communication

Protocol Core

Communication

Protocol API

Communication


Case Study


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Case Study

Acquire Data from simil r ADC using SPI Communication

ADCSPI

FPGA

Why create API?


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Why create API?

Abstraction from Hardware Layer

Reusable

Easy-To-Use

Good Practices when creating API


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Good Practices when creating API

Consistency

Easy To Use

Decoupling

Error Handling

Communication Protocol Messaging API


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C

P

(

CLo

(1

SPI Transaction Commands



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Data tr

FPGA

Deep Look at Code


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Deep Look at Code

Initialize SPI References.vi

Deep Look at Code


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Deep Look at Code

Write Data for SPI Transaction.vi

Deep Look at Code


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Deep Look at Code

Start SPI Transaction.vi

Deep Look at Code


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Deep Look at Code

Read Device Response.vi

Deep Look at Code


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Deep Look at Code

SPI Engine.vi



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Communication

Protocol Core

Communication

Protocol API

Communication


Case Study


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Case Study

Acquire Data from ADC using SPI/I2C Communication Proto

ADCSPI

FPGA

I2C

Communication Protocol Abstraction


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SPI Engine

Sequence of SPI

Commands

(Driver)

NodeGet Data Acquired Data

I/O Node



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SPI Driver

Data Nodes

SPI Engine


I2C E

I2C

Integration into an Existing System Architecture


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SPI Abstraction



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I2C Abstraction



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Summary


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Summary

Design with Timing

- Synchronous Design

- I/O property selection

Software Architecture

- State Machine for Core IP

- Command Based API- Custom I/O Node for abstracting different protocols


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Questions?

Related Links


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Related Links

Serial Peripheral Interface Bus

http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus

SPI API VI Package Manager)

https://github.com/NISystemsEngineering/SPIAPI

Implementing SPI Communication Protocol in LabVIEW FPGA

http://www.ni.com/example/9117/en/#toc2

Timing Analysis on Digital I/O

http://www.ni.com/white-paper/13489/en/
http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bushttps://github.com/NISystemsEngineering/SPIAPIhttp://www.ni.com/example/9117/en/http://www.ni.com/white-paper/13489/en/http://www.ni.com/white-paper/13489/en/http://www.ni.com/white-paper/13489/en/http://www.ni.com/white-paper/13489/en/http://www.ni.com/example/9117/en/https://github.com/NISystemsEngineering/SPIAPIhttp://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus


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Documents

Digital Communication Protocols